Occlusive or moisture-retentive dressings have gained increasing acceptance in treating wounds, in particular pressure sores and ulcers. A wide variety of types of structures are known in the art for use in or as wound dressings, and generally comprise components for receiving, absorbing and retaining exudate. Typically, these dressings include polymeric foams, polymeric films, particulate and fibrous polymers, hydrogels and hydrocolloids. Dressings with at least one of these components promote wound healing by providing a moist environment, while removing excess exudate and toxic components, and further serve as a barrier to protect the wound from secondary bacterial infection. While these known dressings can effectively manage a wound, many have been found to possess certain limitations or disadvantages.
Many known dressings possess the disadvantage of relying solely on a pressure sensitive adhesive layer to secure the dressing to skin. An example of an adhesive is an acrylate glue. While indeed an acrylate glue securely maintains a dressing over a wound, the glue has a tendency to strip the central portion of the dressing from the wound and thus may damage healing tissue.
Many of the known dressings have an absorbent layer that comprises hydrophilic polymeric foam. Unfortunately, many hydrophilic polymeric foam dressings possess the disadvantage of being limited in the amount of exudate that may be absorbed. The limit in exudate absorption of the foam is often directly related to its overall geometrical size prior to absorbing a fluid. Typically, hydrophilic foams may expand only to 10-20% of their original size.
Another disadvantage to hydrophilic foam dressings is that a certain amount of exudate can be “squeezed” out of the foam due to poor liquid retention. The ability of exudates to be squeezed from the foam, and thus the dressing itself, poses a risk of infection and may interfere with the healing of the wound.
Yet another disadvantage with known foam dressings is that absorption of exudate by an absorptive layer, such as foam, in contact with the wound causes the central portion of the applied dressing to swell and push up against the wound. Continued swelling can induce separation of the skin adherent layer from the skin outside the wound area, especially at the border of the wound dressing whereat a “curling” effect may occur. This excessive swelling of the dressing may further lead to leakage of the exudate from the periphery of the dressing, thereby providing a tract for the invasion of pathogenic microorganisms and promoting maceration of the wound site.
Still another disadvantage of hydrophilic foam dressings is that, as cellular tissue grows during the healing process, the cellular tissue may firmly bind to the wound dressing. This is especially the case when the foam dressing has a coarse and porous exterior surface into which cellular tissue will grow. Removing the wound dressing when it is adhered to the wound in this manner will likely traumatize the wound and cause additional pain to the patient. Repeated changing of the wound dressing will result in repeated traumatization of the wound and will ultimately increase the time needed for the wound to completely heal.
For the foregoing reasons, there is a demand for an absorbent structure which prevents wound trauma upon repeated dressing changes, improves the durability and lifetime of the dressing, anatomically conforms to a body portion bearing a wound, possesses suitable fluid uptake, retention and removal properties, and can be securely maintained on a patient's body. It is also desirous to provide an absorbent structure that has suitable absorption properties while dispensing with the need to secure a skin adherent facing layer to the absorbent structure.
A demand also exists for absorbent articles for use in managing moisture in prosthetic devices and for delivering drugs to the body which have similar properties as those described above, such as suitable fluid uptake, retention and removal, and secure placement and anatomical conformance with a body.